A variety of disclosures exist in the art in regard to how to form a supported metal carbide catalyst, including the following:
The impregnation of a support with a water soluble source of the metal alone, followed by calcination to the metal oxide, with subsequent exposure of the oxide to carburizing gases, such as methane/hydrogen (See S. T. Oyama et al., Ind. Eng. Chem. Res., 27, 1639 (1988)) or carbon monoxide (See P. N. Ross, Jr. et al., J. of Catalysis., 48, 42 (1977)) are two ways in which such supported catalysts might be formed. Both carburization reactions necessitate the use of high temperatures on the order of about 900.degree. C. L. Leclercq et al., in U.S. Pat. No. 4,522,708, discusses several supported carbide systems, including work by Mitchell and co-workers in supporting molybdenum on active carbon and other work relating to Group VI metals on alumina (e.g., U.S. Pat. Nos. 4,325,843 and 4,326,992). U.S. Pat. No. 4,325,842 to L. H. Slaugh et al. describes the preparation of supported molybdenum carbide compositions which are formed on a variety of supports, including charcoal and graphite, by impregnating the support with a solution of hexamolybdenum dodecachloride, followed by drying, and then carburization in a carbiding atmosphere at elevated temperature.
Pending U.S. Ser. No. 156,670, filed Nov. 23, 1993 teaches that catalytic metal carbide compositions can be formed by the calcination of a guanidine compound, derivative or adduct with a transition metal salt containing the desired metal component of the carbide.
An improvement of the technology described in this pending application is described in U.S. Pat. No. 5,451,557 in which a water soluble precursor is calcined to form the desired metal carbide catalyst on a support which is an oxidic support, preferably coated with a protective ceramic passivation layer as described and claimed in U.S. Pat. No. 5,338,716.